Optical Metrology and Fabrication for Synchrotron X-ray Optics at NSLS-II

In synchrotron applications, x-ray mirror slope and height specifications are critical, especially when using partially coherent or diffraction-limited x-ray beams. For partially coherent beams, slope errors are specified below 100 nrad RMS across mirrors up to 1000 mm long. For diffraction-limited beams (e.g., in FELs or DLSRs), height errors are specified at 1 nm or sub-nm RMS levels. Meeting these specifications presents major challenges in metrology, requiring advanced tools to characterize mirrors with diverse geometries, including flat, cylindrical, or complex curved surfaces.

The NSLS-II Optical Metrology Laboratory has developed several specialized instruments to meet these challenges. In this webinar, Mourad Idir will discuss how their workflow combines a Fizeau-based stitching interferometer for in-process feedback with a custom ion beam figuring system for fabrication. Final inspections use a range of instruments, including a stitching Shack-Hartmann sensor, nano-accuracy profiler, micro-stitching white light interferometer, and atomic force microscope. Once mirrors pass ex-situ tests, they are installed at the beamline, where in situ tools like the X-ray Hartmann wavefront sensor help align optics by minimizing beam wavefront aberrations.

Subject Matter Level: Intermediate - Assumes basic knowledge of the topic

What You Will Learn:
• Ex situ metrology
• Ion beam figuring
• In situ metrology/alignment

Who Should Attend:
• Undergraduate students with basic knowledge in optics
• General audiences with an interest in optical metrology

About the Presenter: Mourad Idir from National Synchrotron Light Source II

Mourad Idir graduated from Pierre et Marie Curie University in 1994 and began his career at the Commissariat à l’Énergie Atomique, focusing on x-ray plasma diagnostics. After a postdoc at CXRO (Berkeley), he joined CNRS and later worked nearly ten years at Synchrotron SOLEIL, where he led the Optics and Test Beamline group. He joined NSLS-II in 2010, where he now leads the Ex and In Situ Metrology and Optics Fabrication effort and serves as Experimental Development Program Manager. With over 30 years of experience, his expertise spans precision metrology, x-ray optics R&D, instrumentation, and wavefront analysis.